People often have multiple user accounts at different internet websites to serve their disparate needs and interests. However, because most websites maintain the anonymity of users' profile information by allowing users to freely select usernames instead of their real identities, users may provide inconsistent or false profile information, such as name, gender, age, income, marital status, etc., to associate with the username. In some situations, users may provide false information to perform illegal activity on the website.
In order to prevent illegal activity, inconsistent or false profile information provided for a user must be detected. However, identifying the inconsistencies is difficult for a number of reasons. For example, as mentioned before, most websites maintain the anonymity of user profile information. In addition, different websites rarely link their user accounts with other sites or adopt Single-Sign-On technologies, such as openID. Even further, different websites often employ different user-naming and authentication systems. Consequently, there is little or no knowledge of the connectivity among users in a single website or in different websites. That is, there is currently no way to link multiple user accounts or profiles to a single individual who created the multiple accounts.